在 sqlalchemy 中为相同的声明性基础使用不同的模式 [英] Using a different schema for the same declarative Base in sqlalchemy

问题描述

我是 Pyramid 和 SQLAlchemy 的新手.我正在使用 SQLAlchemy 进行 Python Pyramid 项目.我在下面设置了一个简单的模型.我将如何在运行时将其与不同的模式一起使用?这将是一个 PostgreSQL 数据库后端.现在，public"被硬编码到声明性基础模型中.我需要能够使用具有不同模式的相同模型.最好的方法是什么?除非我错过了，否则 SQLAlchemy 的文档对我来说似乎不清楚.

I am new to both Pyramid and SQLAlchemy. I am working on a Python Pyramid project with SQLAlchemy. I have a simple model set up below. How would I go about being able to use this with different schemas at run-time? This will be a PostgreSQL database backend. Right now, "public" is hard-coded into the declarative base model. I would need the ability to use this same model with different schema. What is the best approach? Unless I missed it, the documentation at SQLAlchemy seemed unclear to me.

    from sqlalchemy.ext.declarative import declarative_base
    from sqlalchemy import Column, BigInteger

    __all__ = [
        "LoadTender"
    ]
    __all__.sort()

    Base = declarative_base()


    class LoadTender(Base):
        __tablename__ = "load_tenders"
        __table_args__ = {"schema": "public"}

        id = Column("pkey", BigInteger, primary_key=True)

        def __repr__(self):
            return "" % self.id

我似乎解决了我的问题，我正在更新代码片段以显示我在下面所做的事情.

I have appeared to solve my issue, I am updating the snippet to show what I did below.

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, BigInteger

__all__ = [
    "LoadTender"
]
__all__.sort()

Base = declarative_base()

class ClientMixin(object):
    __table_args__ = {"schema": "client_schema_name"}


class LoadTenderMixin(object):
    __tablename__ = "load_tenders"

    id = Column("pkey", BigInteger, primary_key=True)

    def __repr__(self):
        return "" % self.id


class ClientLoadTender(LoadTenderMixin, ClientMixin, Base):
    pass

推荐答案

我认为您需要为每个模式使用不同的模型.__abstract__ 可以减轻这种痛苦.这是 Paul Yin 的回答......

I think you need a different model for each schema. __abstract__ can make this less painful. This follows on to Paul Yin's answer...

1. 定义一个 __abstract__ LoadTender 模型，这样您就不必继续编码了.

1. Define an __abstract__ LoadTender model, so you don't have to keep coding it.

#base.py
class LoadTender(Base):
    __abstract__ = True
    id = ...
    def __repr__ ...

在每个架构的层次结构中放置一个特定于架构的 Base.

Put a schema-specific Base in the hierarchy for each schema.

#schema1.py
from base import LoadTender

PublicBase = declarative_base(metadata=MetaData(schema='public'))

class LoadTender(PublicBase, LoadTender):
    __tablename__ = 'load_tenders'

对其他架构执行相同操作.

Do the same for other schema.

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